Thermostat



FIG. 1 is a top plan view of a thermostat showing our new design;

FIG. 2 is a front elevational view;

FIG. 3 is a bottom plan view;

FIG. 4 is a right side elevational view;

FIG. 5 is a rear elevational view; and

FIG. 6 is a left-side elevational view thereof. 

The ornamental design for a thermostat, as shown and described. 